Obese People May Have Increased Pain Sensitivity

All of the older adults who completed the study had osteoarthritis of the knee, a disease that causes inflammation and extreme pain in the knees. Participants were given a mild electrical stimulation on their left ankle to measure their pain reflex. The stimulus was given before and after the participants took part in a 45-minute coping skills training session that included a progressive muscle relaxation exercise.

The obese patients showed a greater physical response to the electrical stimulation than did the non-obese people, both before and after the training session. This indicates they had a lower tolerance for the painful stimulation despite reporting, in questionnaires, that they felt no more pain than non-obese people.

“The relaxation procedure helped both groups cope with pain,” said Charles Emery, the study’s lead author and a professor of psychology at Ohio State University. “Additionally, our tests showed both groups had higher physical pain thresholds after the relaxation session. But the obese participants still had a lower threshold for tolerating the pain. This is important because if an obese person begins an exercise program, he may not cognitively experience pain when in fact it is hurting the body on some level,” Emery said. “That could lead to severe pain down the road.”

According to Emery, a small number of studies have looked at pain sensitivity in obese people, but many of these studies report conflicting results. “Our findings show the importance of looking at objective as well as subjective measurements of how the body responds to pain stimuli,” Emery said.